Combustion apparatus



y 1945- J. w. MILLER EIAL 7 2,374,693

COMBUSTION APPARATUS Filed March 6, 194] 2 Sheets-Sheet l JOHN M/ALF/Q'. 3 BY 14444.00 5. 5M/7/7 (MfjiA gA/Q.

May 1, 1945. .1. w. MILLER EI'AL COMBUSTION APPARATUS 2 Sheets-Sheet 2Filed March 6, 1941 Y INVENTOR. JOHN L; M/LL 5? BY 14 4400 5- 'M/T/f(M/r. 74,4 Afi a Patented May' 1, 1945 UNITED STATES PATENT OFFICECOMBUSTION APPARATUS I John W. Miller and Waldo G. Smith, Lansing, Mich,assignors to Motor Wheeh Corporation, Lansing, Mich, a corporation ofMichigan Application March 6, 1941, Serial No. 381,942

. 8 Claims.

This invention relates to combustion apparatus and more particularly toheaters employing vaporizing pot type burners as a source of heat.

The principal object of this invention is to improve the performance ofcombustion apparatus of this type during the so-called high fire stagesof operation. 1

This object is attained primarily by a novel construction andarrangement of the parts of the apparatus adjacent the upper extremityof the burner. More specifically, this object is attained by providing acentrally apertured top wall for the burner, admitting an accuratelymetered volume of air to the apparatus above the top wall through aplurality of air inlet openings, positioning a 'baflle ring above thetop wall, and arranging the top wall, the air inlet openings and thebaflie ring whereby all of the air admitted to the apparatus above thetop wall impinges against either the top wall or the baflle ring and isthereby positively directed into three radially spaced concentric zonesbetween the central Opening in the top wall and the side wall of thecombustion chamber.

By accurately metering all of the air admitted to the apparatus abovethe top wall, uniformly eflicient operation is attained. Heretoforethere has been no real appreciation of the necessity for metering andcontrolling the distribution. of all of the air admitted to theapparatus above the top wall. In many of the prior art-devices theburner is assembled in the combustion chamber in such a manner as topermit a leakage 'of air into the combustion chamber between the biu'nerand the combustion chamber wall. Thus, regardless of the fact that theair admitted to the apparatus above the top wall through the air inletopenings provided for that purpose was accurately metered, the total airadmitted to the apparatus, including that which leaked between theburner and the combustion chamber, was not accurately metered or,distributed. The present invention overcomes this disadvantage of theprior art.

By positively directing the air admitted to the apparatusabove the topwall into three spaced able reduction in the velocity of the air,whereby the flame during high flre operation is lazy and quiet ratherthan vigorous and noisy.

Other objects, more or less incidental to the primary object statedabove, will appear from the following description when read inconnection with the accompanying drawings, wherein- Figure 1 is avertical cross-sectional view or a circulating type space heaterembodying the invention;

Figure 2 is a fragmentary top plan view of the burner employed in theheater of Figure 1;

Figure 3 is a cross-sectional view of the burner taken on substantiallythe line 3-3 of Figure 2;

Figure 4 is a fragmentary cross-sectionalview taken on substantially theline 4-4 of Figure 2;

Figure 5 is a fragmentary cross-sectional view taken on substantiallythe line 5-5 of Figure 2;

Figure 6 is a fragmentary cross-sectional view taken on substantiallythe line 6-6 of FigureZ;

Figure 7 is a fragmentary cross-sectional View taken on substantiallythe line '|--l of Figure 2; and

Figure 8 is a perspective 'view of the anti explosion baflle used in theburner. Y

The invention is embodied in a space heater of the circulating type. Ingeneral the heater comprises an outer casing l0 and a heat chamber shellI I located inside the outer casing and spaced from the walls thereof.In the lower portion of the heat chamber shell'is a burner I! of thevaporizing pot type. The burner is supported on a bottom wall I3 whichis supported by the casing In. Part of" the heat chamber l I above theburner forms the combustion chamber of the heater. 'It communicates witha chimney [5 by means of a fiue outlet l4.

The burner I2 has a bottom wall I6. A sheet metal side wall I! is joinedto the upper edge of the bottom wall It in sealed engagement therewith.The side wall II has an indentation l8 slightly above the upper edge ofthe bottom wall It for a purpose which will appear presently. Near thetop of the side wall is an annular inwardly extending bead I9. Above-thebead l9 and spaced therefrom is an outwardly extending annular bead 20.

The burner side wall is provided with a plurality of air inlet openingsto admit air to the burner. In the apparatus here shown, there are sixhorizontal rows of spaced apart primary air inlet openings 2|, the rowsbeing substantially equidistantly spaced between the bottom wall It ofthe burner and the bead l9. Slightly emcient distribution of the air butalso a desirabove the bead I9 is a horizontal row of secfrom the opening21in the top wall 26.

in Figures 2, 4 and 5. A second row of secondary air inlet openings 23is formed in the lower portion of the bead 20 and inclined upwardly andinwardly through the burner side wall.

The burner side wall I1 is preferably formed from a [plurality of fiatblanks of metal in the manner disclosed in the Valjean Patent No.2,186,156, sheared to the proper shape and coiled into the substantiallyfrusto-conical v shape shown in the drawings. The upright edges arewelded together. Preferably the air inlet openings, both primary andsecondary, are formed in the flat blanks. The beads l9 and 20 are formedby rolling after the side wall is coiled and welded into frusto-conicalshape. The burner side wall is then expanded slightly in suitable dieswhereby to bring it to proper size and roundness. All burners of a givensize are thus made uniform in diameter.

Within the burner 12 is a partition 24 having a large central opening 25therein. A portion of the partition 24 is received in the indentation l8whereby to support it in position in the burner. The partition isinclined upwardly from the indentation and across the burner. The loweredge of the partition 24 is spaced just above the lowermost row ofprimary air inlet openings 2|. The upper edge of the partition 'is atapproximately the level of the next to the uppermost row of primary airinlet openings 2|.

A top wall 26 is mounted in the burner upon the inwardly extending beadIS. The top wall 26 is a substantially frusto-conical upwardlyconverging annulus. It has a large central opening 21 located directlyabove the opening 25 in the partition 24. The upper edge of the top wall26 is located at approximately the level of the top of the burner sidewall, and in any event, above the upper row of secondary air inletopenings 23. The lower edge of the top wall 26 is located below thelower rowof secondary air inlet openings 22.

An anti-explosion bafile 28 is positioned within the burner upon the topwall 26. The antiexplosion bafile 28 is shown best in Figures 4 to 8. Itcomprises an annular rim consisting of a vertical peripheral flange 29,a horizontal annulus 36 extending inwardly therefrom, a vertical wall 3|projecting upwardly from the annulus 38, and another horizontal annulus32 at the top edge of the WH 3|. Projecting inwardly from the annulus 32is a plurality of angularly spaced downwardly opening channels 33. Theinner ends of the channels terminate a short distance The side flangesof the channels are cut away at an angle so as to rest upon the top wall26. The webs of the channels are inclined upwardly and inwardly atanangle between that of the top wall and the horizontal. The channels 33together with the top wall form a plurality of ducts for conveying airtoward the opening 21.

The anti-explosion baille 28 is positioned within the burner so that thelower edge of the peripheral flange 29 is just below the row ofsecondary air inlet openings 23 and above the row of openings 22. Theflange 21 is positioned closely adjacent to the side wall I1 of theburner.

At a plurality of points around its rim the bafile is pressed outwardlyas shown at 34 in Figure 6. The rim of the burner side wall I1 is thenbent inwardly as at 35 to hold the baffle and the top wall in assembledrelationship with the burner.

The heat chamber ll previously mentioned comprises a one pieceside walland a top wall 36 welded in air-tight engagement with the side wall. Theheat chamber shell I I and the burner I2 are so formed and sized thatthe bead 28 tightly fits the heat chamber shell when the burner isinserted into the heat chamber shell. Thus, any leakage between themwill be negligible.

In general, the operation of the present burner is similar to thatdescribed in Valjean Patent No. 2,186,156 granted January 9, 1940, theonly difference being in the so-called high fire stages of operation, i.e., when some or all of the air untilized for combustion is supplied bythe secondary air inlet openings 22 and 23. Reference may be had to thesaid Patent No. 2,186,156 for description of the general operation ofbumers of the present type.

It is during the high fire stage of operation that the construction andarrangement of the top wall 26, the anti-explosion bafile 28 and the airinlet openings 22 and 23 produce the novel by the anti-explosion baflle28 into the apparatus in an inward and upward direction, a part of tneair admitted through these openings-being carried to a point near thecentral opening 21 in the top wall by the channels 33, and the remainderbeing admitted into the apparatus in the areas between the channels.That is to say, the air admitted through the openings 22 is divided intotwo portions, one portion entering the apparatus in an annular zone nearthe opening 21, and the other being admitted to the apparatus in anannular zone concentric with and spaced radially outwardly from thefirst mentioned zone. That part of the air entering through openings 22and carriedinward by the channels 33 to the zone near opening 21 in thetop wall 26 mixes with the rich vapors emerging from the opening 21,forming combustible mixture in that zone even though the vapors as awhole are too rich to burn. Thus a'localized flame near the endsof thechannels is maintained at all times and explosions are effectivelyprevented. This gives the anti-ex: plosion baflie 28 its name.

The air admitted to the apparatus throughthe openings 23 impingesagainst the vertical wall 3| of the anti-explosion baflle 28 whereby itis directed upwardly into the apparatus in an annular zone adjacent theside wall of the combustion chamber. That is to say, the airadmitted-through the air inlet openings 23 enters the apparatus in anannular zone concentric with and spaced radially outwardly from the twozones into which the air admitted through openings 22 is directed.

From the foregoing description it will be apparent that the airsupplied. to the apparatus above the top wall 26 is positively directedso as t localize combustion in the region between the side wall of thecombustion chamber and the central opening 21 in the top wall 26. Itwill be readily understood that by thus locating the combustion adjacentthe side wall of the combustion chamber, a most efiicient transfer ofheat to the medium to be heated is effected.

As previously mentioned; the positive direction of the secondary airinto the three annular zones is accomplished by reason of theimpingement of that air against the top wall 26 or the anti-explosionbaiiie 28. By such impingement the velocity of the air is reduced sothat it rises slowly and gently into the combustion apparatus andthereby produces a lazy, quiet flame. The advantage .of such a flame, inaddition to its quietness, is-

that greater opportunity is afl'orded for transfer of heat to the mediumto be heated, so that baflles or the like are not needed in or adjacentthe chimney outlet to prevent the loss of heat up the chimney.

The inclined top wall 26 increases the volume of the burner and tends tocause a more even upward flow of vapors rising from the burner. This hasa tendency to reduce eddy currents within the burner itself.Furthermore, the upward inclination of the top wall prevents thedownward flow of air and gases, and thereby minicombustion chamber, andthe rest being conveyed into a zone intermediate the first two. Thenumber and size of secondary air inlet openings can be worked out foreach diflerent size of burner to provide maximum efliciency. The flow ofair and vapors is smoothed out by inclining the top wall, and eddycurrents are thereby sub stantially reduced. I

The scope of the invention is indicated in the appended claims:

We claim:

1. Combustion apparatus comprising a combustion chamber having a sidewall, a pot type burner having a side wall, said burner being arrangedvbelow and in open communication with the combustion chamber, a centrallyapertured top wall mounted on the burner, bailie means positioned abovethe top wall of the burner and having an annular portion arranged inspaced relation to the side wall of the combustion chamber, one of saidside walls being provided with a plurality of air inlet openingsarranged about the circumference thereof adjacent the upper extremity ofthe burner to admit air into the apparatus above the burner top wall,the axes of certain of said air inlet openings intersecting said topwall at an angle thereto whereby the air entering through said certainopenings impinges on said top wall, and the axes of certain others ofthe openings in one row intersecting the top wall and the axes of theopenings in the other row intersecting the annular portion of the bafllemeans.

3. Combustion apparatus as defined in claim 1 wherein said air inletopenings are arranged in two vertically spaced horizontal rows, theopenings in one row being positioned above the outer periphery of theannular portion of the baflle means, the openings in the other row beingpositioned below the outer periphery of the annu lar portion of thebaflie means.

4. Combustion apparatus comprising a combus- I tion chamber having aside wall, a pot type burner having a side wall, said burner beingarranged below and in open communication with the combustion chamber, acentrally apertured top wall mounted on the burner, baffle meanspositioned above the top wall of the burner including anannular portionarranged in spaced relation to the side 'wallof the combustion chamber,one of said side walls being provided with a plurality of air inletopenings arranged about the circumference thereof adjacent the upperextremity of the burner to admit air into the apparatus above the burnertop wall, the axes of certain of said air inlet openings intersectingsaid top wall at an angle thereto whereby the air entering through saidcertain openings impinges on said top wall, and the axes of certainothers of said air inlet openings intersecting the annular portion ofsaid baflle at an angle thereby whereby the air entering through saidlast mentioned openings impinges on the annular portion of said baflle,and additional baflle means for directing the air admitted throughcertain others of said air inlet openings toward the central opening inthe top wall.

5. Combustion apparatus as defined in claim 4 wherein said air inletopenings are arranged in two vertically spaced horizontal rows with onerow located above and the other row located below the lower extremity ofthe annular portion of said baiile means.

6. Combustion apparatus comprising a combustion chamber having a sidewall, a pot type burner having a side wall, said burner being arrangedbelow and in open communication with the combustion chamber, a centrallyapertured top wall for the burner, and a baflie above said top wall, oneof said side walls having a plurality of air inlet openings thereinarranged about the circumference thereof, the axes of certain of saidair inlet openings intersecting said top wall at an angle thereto, andthe axes of the remainder of said air inlet openings intersecting saidbaflle at an angle thereto, said baflle being constructed and arrangedto direct a portion of the air impinging against the top wall toward thecentral aperture in the latter.

7. Combustion apparatus comprising a combustion chamber having a sidewall, a pot type burner having a. side wall, said burner being arrangedbelow and .in open communication with the combustion chamber, acentrally apertured top wall mounted on the burner, baflie meanspositioned above the top wall of the burner, one of said side walls,being provided with a plurality of air inlet openings arranged about thecircumference thereof adjacent the upper extremity of the burner toadmit air into the apparatus above the burner top wall, the axes ofcertain of said air .inlet openings intersecting said baflie means at anangle thereto whereby the air entering said certain air inlet openingsimpinges on said bafiie means, the axes of the remainder of said airinlet openings intersecting said top wall at an angle thereto wherebythe air entering through said last mentioned openings impinges on saidtop wall, said bafile means including por..

other portions cooperating with said topwall to wall into an annulardirect a part of the air impinging on the top inner zone adjacent theaperture in the top wall, said baflle means having still other portionsdirecting part of the air impinging on the top wall into an annularintermediate zone.

rows of air inlet openings therein spaced about the circumferencethereof above the top wall, the axes of the openings in the lower rowbeing directed toward said top wall, a substantial portion 'of the axialprojection of each of the openings in said lower row intersecting saidcircumferentially continuous portion of said top wall at an anglethereto, said ballle being constructed and arranged to direct a portionof the air impinging against the top wall toward the central aperture inthe top wall.

JOHN W. MIILER. WALDO G. SMITH.

